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Room 3-470 77 Massachusetts Ave. Cambridge, MA 02139. Phone: (617) 253-1953 Fax: (617) 258-6427 http://pergatory.mit.edu/. The Modified MiniMill™. A small milling machine with linear motors and air bearing. By: Roger Cortesi rcortesi@mit.edu http://pergatory.mit.edu/rcortesi/.
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Room 3-470 77 Massachusetts Ave. Cambridge, MA 02139 Phone: (617) 253-1953 Fax: (617) 258-6427 http://pergatory.mit.edu/ The Modified MiniMill™ A small milling machine with linear motors and air bearing. By: Roger Cortesi rcortesi@mit.edu http://pergatory.mit.edu/rcortesi/ Precision Engineering Research Group Massachusetts Institute of Technology, Mechanical Engineering Department
Using the Axtrusion™ as a building block, create a desktop Milling Machine “I will call it… MiniMill™”
MiniMill™ Functional Requirements • A part accuracy of 0.001” (25.4 mm) • A work volume of 300 x 300 x 300 mm • A manufacturing cost of $20,000
MiniMill™ Prototype Budget Materials Assume that the in-production manufacturing cost between 30 and 50% of the prototype cost.
MiniMill™ Production Budget Estimated Material Costs
Some Competing Machines The Compact DMC™ (left), and the XV Tabletop™ (middle) Machining Centers by Defiance. The Benchman™ Series (right) by Light Machines.
Space Efficiency • Three times the Work Vol / Machine Vol of other small machines • Twice the Work Vol / Floor Space of DMC Compact Center™ • Four times the Work Vol / Floor Space of the Other Machines
Some Other Initial Concepts Sawyer Motor for the X & Y Directions. Traditional or Combined Unit for the Z axis and Spindle Two Axtrusions on the base (X &Y) and an Axtrusion for the Z axis.
MiniMill™, The Final Concept One Axtrusion on the Base (X) One on the Gantry (Y) and one for the Z This allows for two identical “L”s to make the structure.
Final Concept Features • Only Four (4) Major Parts • “Hot” Swappable Spindle Interface • Auto-Tool Changer Easily Accommodated • More Crash Resilient
The Model Results(via a MatLab script) Error at the Tool Tip (microns) vs. Tool Position